Image forming apparatus for printing images properly arranged relative to index tab

ABSTRACT

An image forming apparatus prints images on print sheets, and insets tab-index sheets between the printed print sheets. The image forming apparatus includes an orientation detecting unit which detects an orientation of a print sheet being supplied, a rotation-angle selecting unit which selects a rotation angle of an image such that the image is arranged in an orientation matching the detected orientation of the print sheet and in a predetermined positional relationship with a tab of the tab-index sheets, and a printing unit which prints the image being rotated by the selected rotation angle.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of Ser. No. 10/384,595,filed Mar. 11, 2003 now U.S. Pat. No. 7,492,471, the entire contents ofwhich is incorporated herein by reference. U.S. Ser. No. 10/384,595 isbased upon and claims benefit of priority from the prior Japanese PatentApplication Nos. 2002-067572, filed on Mar. 12, 2002, 2002-067573, filedon Mar. 12, 2002, and 2003-038748, filed on Feb. 17, 2003.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to image forming apparatusescapable of printing on index sheets, and particularly relates to animage forming apparatus and an image processing program which arecapable of proper printing on index sheets by avoiding inconsistencybetween the printing orientation and the index direction.

2. Description of the Related Art

Widespread use of DTP (desktop publishing) facilitated by the spread ofpersonal computers is not only changing household activities but alsothe type of work that is conducted at office. In the conventionalprocess of bookbinding, a fully bound book will not be available for anumber of days after requesting bookbinding to a bookbinder. Imageforming apparatuses are nowadays connected to peripheral devices capableof bookbinding, and can take care of a front cover, chapter delimiters,stapling, and punching, providing a fully bound book on the spot.

In such bookbinding by image forming apparatuses, it is well known toinsert chapter-separating sheets (e.g., see Japanese Patent ApplicationPublication No. 2001-278530). If an tab-index sheet having a tabprojecting from a standard-size sheet is used as a chapter-separatingsheet, readers can easily find the chapter that the readers wish toread.

A tab-index sheet, however, is generally comprised of a standard-sizesheet and a tab projecting from this standard-size sheet, as describedabove. In most image forming apparatuses of the conventional art, theprojecting tab needs to be situated on the rear side when the sheet iscarried inside the apparatus.

This is because the printing method of conventional image formingapparatuses requires such positioning. When images are to be printed onsheets, generally, the front end of the sheets being conveyed arealigned with the front tip of the images. To this end, image formingapparatuses conveys the sheets such that the front end of the sheetsbeing conveyed is struck against the resist rollers, therebycompensating for skews generated during the conveyance of the sheets andcarrying out printing at proper timing.

If a tab is situated at the front end in such a printing scheme asdescribed above, image forming apparatuses would have difficultyaligning the front tip of images to the front end of tab-index sheetsunless special equipment is provided. Accordingly, tabs are alwayspositioned at the rear end when tab-index sheets are conveyed.

When a sheet that is horizontally or vertically asymmetrical because ofthe indexing tab is used, an orientation in which an image is printedshould be taken care of. If the tab should come at the top right cornerof an image, the image should be printed in such a position.

Image forming apparatuses ate generally provided with a function torotate a scanned image when printing the image. If a A4 document sheetis set in a vertical position as viewed from the user, and if a A4 printsheet is set in a horizontal position in an image forming apparatus, forexample, the image scanned in the vertical position can be rotated to bein a horizontal position so as to match the position of-the print sheet.

The rotation of an image may be set to 0 degree, 90 degrees, 180 degreesor 270 degrees if there are no particular limitations.

In general, the rotational angle of an image is determined based on analgorithm that takes into account an operation mode relating to adocument size, sorting, stacking, tray selection, etc.

Conventional image forming apparatuses do not take into account theorientation of an image relative to an indexing tab such as when thetabs come at the right-hand-side edge of the book that is bound on theleft-hand-side edge.

Further, a problem arises when the direction of the indexing tab doesnot match the position of stapling or the position of punching as in thecase in which the orientation of printed images is limited by staplingor punching.

Moreover, conventional image forming apparatuses do not match theorientation of images with the orientation of the first image at thetime of printing by using the first image of a document as a reference.Because of this, images printed on different pages may be oriented indifferent directions, thereby making it difficult to bind the book afterprinting.

Accordingly, there is a need for an image forming apparatus and an imageprocessing program which can properly set the orientation of images soas to make it match the direction of a tab of a tab-index sheet.

SUMMARY OF THE INVENTION

It is a general object of the present invention to provide an imageforming apparatus and an image processing program that substantiallyobviates one or more problems caused by the limitations anddisadvantages of the related art.

Features and advantages of the present invention will be presented inthe description which follows, and in part will become apparent from thedescription and the accompanying drawings, or may be learned by practiceof the invention according to the teachings provided in the description.Objects as well as other features and advantages of the presentinvention will be realized and attained by an image forming apparatusand an image processing program particularly pointed out in thespecification in such full, clear, concise, and exact terms as to enablea person having ordinary skill in the art to practice the invention.

To achieve these and other advantages in accordance with the purpose ofthe invention, the invention provides an image forming apparatus whichprints images on print sheets, and insets tab-index sheets between theprinted print sheets. The image forming apparatus includes anorientation detecting unit which detects an orientation of a print sheetbeing supplied, a rotation-angle selecting unit which selects a rotationangle of an image such that the image is arranged in an orientationmatching the detected orientation of the print sheet and in apredetermined positional relationship with a tab of the tab-indexsheets, and a printing unit which prints the image being rotated by theselected rotation angle.

According to another aspect of the present invention, the image formingapparatus as described above further includes a unit which selects thetab-index sheets by specifying the orientation of the tab-index sheets.

According to another aspect of the present invention, the image formingapparatus as described above further includes a unit which selects atray that contains tab-index sheets matching a size of the images.

According to another aspect of the present invention, saidrotation-angle selecting unit rotates the image such that a tab positionspecified for the image matches a tab position of the selected tab-indexsheets.

According to another aspect of the present invention, saidrotation-angle selecting unit checks whether the image is a first image,said rotation-angle selecting unit arranging the image in an orientationmatching an orientation of the print sheet if the image is the firstimage, and arranging the image in an orientation matching an orientationof a sheet on which the first image is printed if the image is not thefirst image.

According to another aspect of the present invention, a record mediumhas a program embodied therein for causing a processor to select arotation angle of an image that is to be printed by an image formingapparatus using tab-index sheets. The program includes a program codeconfigured to detect an orientation of a print sheet being supplied, anda program code configured to select the rotation angle of the image suchthat the image is arranged in an orientation matching the detectedorientation of the print sheet and in a predetermined positionalrelationship with a tab of the tab-index sheets.

According to another aspect of the present invention, a record mediumhas a program embodied therein for causing a processor to select arotation angle of an image that is to be printed by an image formingapparatus. The program includes a program code configured to checkwhether the image is a first image, and a program code configured toselect the rotation angle of the image such that the image is arrangedin an orientation matching an orientation of a print sheet if the imageis the first image, and configured to select the rotation angle of theimage such that the image is arranged in an orientation matching anorientation of a sheet on which the first image is printed if the imageis not the first image.

According to another aspect of the present invention, a record mediumhas a program embodied therein for causing a processor to select arotation angle of an image that is to be printed by an image formingapparatus using tab-index sheets. The program includes a program codeconfigured to detect an orientation of a print sheet being supplied, aprogram code configured to select the rotation angle of the image suchthat the image is arranged in an orientation matching the detectedorientation of the print sheet and in a predetermined positionalrelationship with a tab of the tab-index sheets, a program codeconfigured to check whether the image is a first image, and a programcode configured to select the rotation angle of the image such that theimage is arranged in an orientation matching an orientation of the printsheet if the image is the first image, and configured to select therotation angle of the image such that the image is arranged in anorientation matching an orientation of a sheet on which the first imageis printed if the image is not the first image.

According to another aspect of the present invention, a record mediumhas a program embodied therein for causing a processor to controlprinting of an image that is printed by an image forming apparatus usingtab-index sheets. The program includes a program code configured toselect a position of a tab relative to the image, and a program codeconfigured to rotate the image such that the selected position of a tabrelative to the image matches a position of a tab of the tab-indexsheets.

According to another aspect of the present invention, a record mediumhas a program embodied therein for causing a processor to controlprinting of an image that is printed by an image forming apparatus usingtab-index sheets. The program includes a program code configured toselect two positions of a tab relative to the image, and a program codeconfigured to rotate the image such that a position of a tab of thetab-index sheets matches either one of the two selected positions of atab relative to the image.

According to another aspect of the present invention, a record mediumhas a program embodied therein for causing a processor to controlprinting of an image that is printed by an image forming apparatus usingtab-index sheets. The program includes a program code configured toselect two positions of a tab relative to the image while specifying oneof the two positions as a preferred position, and a program codeconfigured to rotate the image such that a position of a tab of thetab-index sheets matches either one of the two selected positions of atab relative to the image where said specified one of the two selectedpositions is preferred over another one if both of the two selectedpositions of a tab relative to the image match the position of a tab ofthe tab-index.

According to another aspect of the present invention, the programfurther includes a program code unit configured to suspend the printingof the image and notify a user if the selected position of a tabrelative to the image does not match the position of a tab of thetab-index sheets or if the position of a tab of the tab-index sheetsdoes not match either one of the two selected positions of a tabrelative to the image.

As described above, the present invention provides an image formingapparatus and a record medium having a program embodied therein forselecting the orientation of an image such as to make it match theposition of a tab of a tab-index sheet.

Other objects and further features of the present invention will beapparent from the following detailed description—when read inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustrative drawing showing a schematic construction of amulti-function unit that is an example of an image forming apparatus ofthe present invention;

FIG. 2 is a block diagram showing a set of software units, a starting-upunit, and hardware resources;

FIG. 3 is a block diagram showing an example of the hardwareconstruction of the multifunction unit;

FIG. 4 is an illustrative drawing showing the operation unit providedfor a user to enter instructions;

FIG. 5 is a flowchart of a procedure of determining the rotation angleof an image in order to arrange the image in a correct position relativeto the tab of a tab-index sheet;

FIG. 6 is a flowchart of a procedure for aligning all the images of adocument in the same direction as the first image of the document;

FIG. 7 is a flowchart of the procedure for aligning images in the sameorientation as the first image and in the correct positional relationwith the tab of tab-index sheets;

FIG. 8 is an illustrative drawing showing an operation unit whichdisplays an index-print-mode key;

FIG. 9 is an illustrative drawing showing a screen for selecting animage orientation of tab-index sheets;

FIG. 10 is a flowchart of a printing procedure in a case in which thereis a single selected position with respect to printing on tab-indexsheets;

FIG. 11 is an illustrative drawing showing the way an image is printedas described above;

FIG. 12 is an illustrative drawing showing the way an image is printedwhen the image having a size as shown by dotted lines can fit in atab-index sheet regardless of the orientation of the image;

FIG. 13 is a flowchart of a procedure for printing images by specifyingtwo preferred directions as the direction of an index tab;

FIG. 14 is an illustrative drawing showing images that are printedaccording to the procedure of FIG. 13;

FIG. 15 is a flowchart of a procedure relating to the directions of animage index tab and a sheet index tab;

FIG. 16 is a flowchart of a procedure relating to a case in which a modeinvolving tab-index sheets and a punch mode are both used;

FIG. 17 is an illustrative drawing showing variations of the combinationof the specified position of an index-tab and the specified position ofpunch holes; and

FIG. 18 is a flowchart of a procedure for warning a user upon suspensionof a job.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following, embodiments of the present invention will be describedwith reference to the accompanying drawings.

FIG. 1 is an illustrative drawing showing a schematic construction of amulti-function unit 701 that is an example of an image forming apparatusof the present invention.

The multi-function unit 701 includes an automatic-document feeder(hereinafter referred to ADF) 1, a document platform 2, a scan unit 50,an imaging unit 57, a development unit 27, a fixing unit 17, andsheet-supply devices 11, 12, and 13. The multi-function unit 701 furtherincludes devices such as an operation unit, sheet-supply rollers,clutches, motors, etc., which are not shown.

The ADF 1 automatically feeds document sheets that are placed on thedocument platform 2. In detail, a stack of document sheets is placed onthe document platform 2 with their document images facing up. Pressingdown of a print key 33 of an operation unit 30 (see FIG. 4) starts thefeeding of the document sheets. The document sheets are taken out one byone from the bottom of the stack, and are carried to a predeterminedposition on a contact glass 6 by sheet-supply rollers 3 and sheet-supplybelt 4.

A count function counts up the count of document sheets each time thesupply of a sheet is completed, thereby controlling the number ofdocument sheets that are scanned. A document sheet positioned on thecontact glass 6 is scanned by the scan unit 50, thereby producing imagedata. The document sheet for which scanning is finished is ejected bythe sheet-supply belt 4 and ejecting rollers 5. If a document detector 7detects the presence of a next document sheet on the document platform2, this document sheet is supplied on to the contact glass 6 in the samemanner as the preceding sheet. The sheet-supply rollers 3, thesheet-supply belt 4, and the ejecting rollers 5 are driven by motors.

The imaging unit 57 controls a laser beam of a laser outputting unit 58based on image forming data that is generated from the image scanned bythe scan unit 50, and forms a latent image by scanning the laser beam ona photosensitive body 15. The photosensitive body 15 carrying the latentimage ends up having toner attached to the latent image as it passes thedevelopment unit 27. This creates a toner image. The conveyer belt 16conveys a sheet at a rate that matches the rotation of thephotosensitive body 15 that carries the toner image, therebytransferring the toner image from the photosensitive body 15 to thesheet.

Print sheets or tab-index sheets stacked in the first tray 8, the secondtray 9, and the third tray 10 are carried by the first sheet-supplydevice 11, the second sheet-supply device 12, and the third sheet-supplydevice 13, respectively, and are further conveyed by a vertical conveyerunit 14 to the photosensitive body 15. A sheet having a transferredtoner image is processed by the fixing unit 17 that fixes the image, andis ejected on to a paper-ejection tray 19 by a paper-ejection unit 18.

When images are to be printed on both sides of a sheet, a sheet takenout from the first tray 8, the second tray 9, or the third tray 10 isnot led to the paper-ejection tray 19 after the image formation.Instead, the sheet is let into a double-side.-sheet-carrying path 113,and is flipped over by an inverting unit 112, followed by being suppliedto a double-sided-sheet-carrying unit 111. This sheet is then suppliedto the vertical conveyer unit 14 again, and an image is printed on asecond side of the sheet, followed by the ejection of the sheet.

When there is a need to eject a sheet after flipping it over, a sheetthat is flipped over by the inverting unit 112 is sent to aninverted-sheet-conveyer path 114 rather than to thedouble-sided-sheet-carrying unit 111, followed by the ejection of thesheet.

The photosensitive body 15, the conveyer belt 16, the fixing unit 17,the paper-ejection unit 18, and the development unit 27 are driven bymotors. The first sheet-supply device 11, the second sheet-supply device12, and the third sheet-supply device 13 are driven by the torque of amain motor propagated by respective sheet-supply clutches. The verticalconveyer unit 14 is driven by the torque of the main motor that ispropagated by an intermediate clutch.

When the auto-selection of a paper-sheet tray (APS) is activated, aproper paper-sheet tray is automatically selected based on a copy modeand a document size, which will be described later. When the manualselection of a paper-sheet tray is chosen, the user selects a desiredtray. When a front-cover mode, a chapter separation mode, or a sheetinsertion mode is chosen, a front-cover tray and a tab-index sheet trayare selected in addition to the paper-sheet tray based on predeterminedsettings or given selection.

In the following, software installed in the multi-function unit 701 willbe described with reference to FIG. 2. FIG. 2 is a block diagram showinga set of software units 702, a starting-up unit 703, and hardwareresources 704.

The starting-up unit 703 is driven first at the time of power on of themulti-function unit 701, and activates an application layer 705 and acontroller 706. The starting-up unit 703 may read programs of theapplication layer 705 and the controller 706 from a hard-drive(hereinafter referred to as HD) or the like, and loads the programs tothe memory space, followed by executing them. The hardware resources 704includes a black-&-white laser printer 725, a color laser printer 726,and hardware resources 724 that include a scanner, a facsimile, etc.

In the present embodiment, the multifunction unit 701 may be providedonly one of the black-&-white laser printer 725 and the color laserprinter 726.

The set of software units 702 includes the application layer 705 and thecontroller 706, which run on an operation system (hereinafter referredto as OS) such as a UNIX. The application layer 705 includes programsfor performing user-service-specific processes that relate to imageformation where such services may include printing, copying, faxing, andscanning.

The application layer 705 includes a printer application 709 forprinting, a copy application 710 for copying, a facsimile application711 for faxing, and a scanner application 712 for scanning.

The controller 706 includes a control service layer 707, a systemresource manager 721, and a handler layer 708. The control service layer707 analyzes a process request issued by the application layer 705, andgenerates an acquisition request for acquiring the hardware resources704. The system resource manager (SRM) 721 controls one or more thehardware resources 704, and arbitrates between acquisition requestsissued by the control service layer 707. The handler layer 708 controlsthe hardware resources 704 in response to an acquisition request made bythe SRM 721.

The control service layer 707 includes a network control service (NCS)713 corresponding to a communication part, a remote service (RS) 714, anoperation panel control service, (OCS) 715, a facsimile control service(FCS) 716, an engine control service (ECS) 717, a memory control service(MCS) 718, an on-demand update service (OUS) 719, and a system controlservice (SCS) 720. In this manner, the control service layer 707 isconfigured to include one or more service modules.

The controller 706 is configured to include an API (applicationinterface) 728 that is capable of receiving a process request from theapplication layer 705. This is done by use of predefined functions ofthe controller 706. The OS executes the individual software units of theapplication layer 705 and the controller 706 as concurrently runningprocesses.

The process of the NCS 713 provides services that can be shared byapplications in need of a network I/O. The process of NCS 713 maydistribute data to individual applications as the data is received fromthe network according to various protocols, and may serve as anintermediary when data is sent from individual applications to thenetwork.

For example, the NCS 713 controls data communication with networkequipment connected through the network by use of HTTP (HyperTextTransfer Protocol) based on the httpd (hypertext transfer protocoldaemon).

The process of the RS 714 renders services using a network such as theInternet. The process of the OCS 715 controls an operation panel thatserves as a communication means between a user and device control. Theprocess of FCS 716 provides the application layer 705 with APIs used forfacsimile transmission/reception through a network such as a PSTN or anISDN, facsimile scanning, facsimile printing, theregistration/referencing of facsimile data stored in backup memory, etc.

The process of the ECS 717 corresponds to an orientation detecting meansand a rotation-angle setting (selecting) means, and controls an engineunit such as the black-&-white laser printer 725, the color laserprinter 726, and the hardware resources 724. The process of the MCS 718attends to memory control such as the acquisition and releasing ofmemory and the use of an HD. The process of the OUS 719 downloads aprogram to the memory in response to a notice from the network.

The process of the SCS 720 attends to application control,operation-panel control, system-screen display, LED display,hardware-resource control, interruption application control, etc.

The process of the SRM 721 together with the process of the SCS 720attends to the system control, and controls the hardware resources 704.The process of the SRM 721 arbitrates in response to acquisitionrequests issued from the upper layer that make use of the hardwareresources 704 such as the black-&-white laser printer 725 and the colorlaser printer 726, and attends to operation control.

In detail, the process of the SRM 721 checks whether the requestedresource of the hardware resources 704 is available. If such a resourceis available, the process of the SRM 721 notifies the upper layer thatthe requested resource of the hardware resources 704 is available.Further, the process of the SRM 721 attends to the scheduling of use ofthe hardware resources 704 in respect of the acquisition requests issuedfrom the upper layer, and carries out the requested processing such asthe supply of sheets and the formation of images in the printer engine,memory allocation, file generation, etc.

The handler layer 708 includes a facsimile control unit handler (FCUH)722 for controlling a facsimile control unit (FCU), and further includesan image memory handler (IMH) 723 for allocating a memory space to aprocess and controlling the memory allocated to the process. The SRM 721and the FCUH 722 utilize an engine I/F 727 that allows a process requestto be sent to the hardware resources 704 by use of predefined functions,thereby processing the process request for the hardware resources 704.

In this manner, the multi-function unit 701 uses the controller 706 toattend to the central control of processes required and shared byindividual applications. In what follows, the hardware configuration ofthe multi-function unit 701 will be described.

FIG. 3 is a block diagram showing an example of the hardwareconstruction of the multifunction unit 701. The multi-function unit 701includes a controller board 750, an operation unit 30, an FCU 740, anengine 743, and a plotter 744 that serves as a printing means. The FCU740 includes a G3-standard unit 747 and a G4-standard unit 748.

The plotter 744, which is a general device that prints an image on apaper sheet, corresponds to the photosensitive body 15 of FIG. 1 in thenarrow sense of the term, and corresponds to all the printing-relatedhardware and software of the multifunction unit 701 in the broad senseof the term.

The controller board 750 includes a CPU 731, an ASIC 736, an HD 738, alocal memory (MEM-C) 737, a system memory (MEM-P) 732, a north bridge(NB) 733, a south bridge (SB) 734, a network interface card (NIC) 745, aUSB device 741, an IEEE-1394 device 742, and a centronics device 746.

The operation unit 30 is connected to the ASIC 736 of the controllerboard 750. The SB 734, the NIC 745, the USB device 741, the IEEE-1394device 742, and the centronics device 746 are connected to the NB 733through a PCI bus.

The FCU 740, the engine 743, and the plotter 744 are connected to theASIC 736 of the controller board 750 via the PCI bus.

In the controller board 750, the ASIC 736 is connected to the localmemory 737, the HD 738, etc., and is connected to the CPU 731 via the NB733 that is a CPU chip set. As the CPU 731 and the ASIC 736 areconnected together via the NB 733, things can be taken care of even ifthe interface of the CPU 731 is not disclosed to the public.

The ASIC 736 and the NB 733 are not connected through the PCI bus, butare connected through an AGP (accelerated graphics port) 735. Connectingthe ASIC 736 with the NB 733 through the AGP 735, rather than the PCIbus that is relatively slow, can avoid diminishing performance since itis necessary to control one or more processes of the application layer705 and the controller 706 shown in FIG. 2.

The CPU 731 attends to overall control of the multi-function unit 701.The CPU 731 executes the NCS 713, the RS 714, the OCS 715, the FCS 716,the ECS 717, the MCS 718, the OUS 719, the SCS 720, the SRM 721, theFCUH 722, and the IMH 723 as processes running on the OS. Further, theCPU 731 activates and executes the printer application 709, the copyapplication 710, the facsimile application 711, and the scannerapplication 712 that constitute the application layer 705.

The NB 733 is a bridge used for providing connections between the CPU731, the system memory 732, the SB 734, and the ASIC 736. The systemmemory 732 serves as a rendering memory of the multi-function unit 701.The SB 734 is a bridge that provides connections between the NB 733, aROM, a PCI bus, and peripheral devices. The local memory 737 is used asa copy-purpose image buffer and a code buffer.

The ASIC 736 is an IC dedicated for image processing, and includeshardware elements for image processing. The HD 738 is a storage thatstores image data, document data, programs, font data, various forms,and so on. The operation unit 30 receives operational inputs from theuser, and provides display for the user.

In the following, the operation unit 30 will be described. FIG. 4 is anillustrative drawing showing the operation unit 30 provided for a userto enter instructions. The operation unit 30 includes mode keys 31 forselecting various modes, a key pad 32 for indicating how many copies areto be made, a print key 33 for starting copying or printing, a stop key34 for stopping copying, a test print key 35 for outputting a testprint, a document adding/inserting key 36, and a mode reset key 37.

The mode keys 31 for selecting various modes and displaying messagesinclude a auto-density key 311 for changing density, a density increasekey 320, a density decrease key 321, a tray selecting key 323, aselected-tray displaying unit 323 for displaying a selected tray, anautomatic sheet selection key 312, a scale key 313 for changing thescale, a sort key 314 for sorting, a staple key 315 for selecting stablesettings, a chapter separation key 316, a document orientation key 317for setting the orientation of a document, a front cover key 318, adisplay unit 319 for displaying messages for users, and other keys (notshown) including a print-mode key, a user-mode key, a rotation-mode key,etc.

In what follows, modes will be described. The chapter separation mode isused to provide printing on tab-index sheets when document imagesselected by a user are to be printed. Here, the tab-index sheets arechosen through other settings. The document orientation mode is used tomake settings regarding an orientation in which a scanned document is tobe printed. This enables printing to take into account the orientationof the scanned image even when a document is an A3 document or the likethat can only be oriented in one direction in the ADF or on the contactglass.

The front-cover mode is used when front-cover sheets selected by othersettings are to be used for the beginning of the document and for theend of the document. The print mode includes a page-number printingfunction that automatically prints page numbers, and further includes astamp printing function that inserts a registered picture as part ofprinting. In either mode, the user can select a page number from whichthe relevant printing starts. A user code mode allows a user to enter anumber that identifies each user, thereby making it possible to controlthe number of uses and the number of copied pages on a user-specificbasis. The rotation mode key allows an image to be rotated 0 degrees, 90degrees, 180 degrees, or 270 degrees at the time of printing.

When tab-index sheets are used for chapter separation, selection is alsomade with respect to the positioning of the tab relative to images.Dedicated keys may be provided on the operation unit 30 for the purposeof such selection, or the initial setting may be utilized to make suchselection.

When tab-index sheets are printed, the indexing tabs are positioned atthe rear end of the sheets that are being conveyed, as previouslydescribed.

With regard to the staple mode that can be selected at the time ofprinting, there is a limit to the number of copied pages that can bestapled together, depending on the type of a finisher and the type andsize of paper sheets. If the number of copied pages exceeds this limit,a message will be displayed on the operation unit 30 to notify the userthat stapling cannot be done. Such a decision as to stapling can be madeprior to the start of printing operation based on the number of documentpages and the printing mode indicative of either single-side printing ordouble-side printing.

The user operates the keys on the operation unit 30 to select a copymode, and presses the print key 33, which initiates the scanning ofdocument sheets in the case of a copying operation, or initiates aprinting job in the case of a printer operation. With the start of suchan operation, software for supplying and printing paper sheets executesa selected copy mode on a printing-surface-by-printing-surface basis.The printing-surface-by-printing-surface processing is referred to as aprocess. A printing process is generated and issued to the ECS 717,thereby achieving sheet-conveyance control and printing operations.After the completion of printing, the completion of process execution isreported. When all the processes are completed, the printing operationcomes to an end.

In the following, processing according to the present embodiment will bedescribed. First, a description will be given of the processing forrotating images. Next, a description will be given with regard to theprocessing for positioning images in a correct position relative to thetab of the tab-index sheet.

When the chapter separation mode is selected, and when tab-index sheetsare selected as the chapter delimiter, there is a need to arrange imagesin a correct position relative to the position of the tab of tab-indexsheets. Here, arranging images in a correct position relative to theposition of the tab means arranging images constantly in the sameorientation such as in an upright position or in a horizontal positionwith the top end of the image being on the left, with such arrangementbeing kept when the tab-index sheets and other print sheets are alignedsuch that the longer side of the tab-index sheets matches the longerside of the other print sheets.

FIG. 5 is a flowchart of a procedure of determining the rotation angleof an image in order to arrange the image in a correct position relativeto the tab of a tab-index sheet. This procedure is carried out by theECS 717.

The procedure will be described with reference to FIG. 5. When the userselects the chapter separation mode, and presses the print key 33, themulti-function unit 701 starts scanning the stack of document sheets.The multi-function unit 701 selects a print-sheet tray and atab-index-sheet tray, and starts the procedure for determining therotation angle. The multi-function unit 701 is provided with apreferred-selection function that selects one of the horizontal sheettray or the vertical sheet tray according to the preset preference.

At step S1, a check is made as to whether the orientation of a sheet isthe same as the orientation of tab-index sheets. The orientation of thesheet is the same as the orientation of tab-index sheets when the longer(or shorter) side of the sheet and the longer (or shorter) side of thetab-index sheets extend in the same direction.

If the two orientations are the same, the ECS 717 checks at step S2whether an image is in the correct positional relationship with theindex tab. If it is in the correct positional relationship, the ECS 717sets an angle to 0 degree at step S3, which is then determined as therotation angle at step S11. If it is found at step S2 that the image isnot in the correct positional relationship, the ECS 717 checks at stepS4 whether the image being rotated 180 degrees is in the correctpositional relationship with the index tab. If it is in the correctpositional relationship, the ECS 717 sets an angle to 180 degrees atstep S5, which is then determined as the rotation angle at step S11.Rotation by 0 degree or by 180 degrees as described above can cope withthe case in which the orientation of the sheet is the same as theorientation of the tab-index sheets.

If it is found at step S4 that the image is not in the correctpositional relationship, the ECS 717 halts the procedure at step S10 ashaving failed to identify the condition.

If it is found at step S1 that the orientation of the sheet is not thesame as the orientation of the tab-index sheets, the ECS 717 checks atstep S6 whether the image being rotated 270 degrees is in the correctpositional relationship with the index tab. If it is in the correctpositional relationship, the ECS 717 sets an angle to 270 degrees atstep S7, which is then determined as the rotation angle at step S11.

If the image being rotated 270 degrees is not in the correct positionalrelationship, the ECS 717 checks at step S8 whether the image beingfurther rotated 180 degrees is in the correct positional relationshipwith the index tab. If it is in the correct positional relationship, theECS 717 sets an angle to 90 degrees at step S9 by adding 180 degrees to270 degrees. The 90-degree angle is then determined as the rotationangle at step S11. If it is found at step S8 that the image beingfurther rotated 180 degrees is not in the correct positionalrelationship, the ECS 717 halts the procedure at step S10 as havingfailed to identify the condition.

The procedure described above is carried out with respect tohorizontally positioned sheets or vertically positioned sheets accordingto the selected tray type.

In this manner, document images are aligned in a correct orientationrelative to the tab of tab-index sheets. After printing, therefore, theorientation of images is constant with respect to the tab, whicheliminates a need to rotate the printed pages on which images areprinted upside down.

In the following, a description will be given of another embodiment forimage rotation in which all the images of a document are aligned in thesame direction as the first image of the document.

In this procedure, a print sheet for the first image is selectedaccording to the preset preferred-sheet-tray setting.

FIG. 6 is a flowchart of a procedure for aligning all the images of adocument in the same direction as the first image of the document.

This procedure starts when a preferred-sheet-tray setting is made andthe print key 33 is pressed. As the multi-function unit 701 startsscanning a stack of document sheet, the ECS 717 checks at step S21whether a scanned image is the first image.

If it is the first image, the ECS 717 checks at step S22 whether theorientation of the image is the same as the orientation of a sheet ofthe selected sheet tray. The orientation of the image is the same as theorientation of a sheet of the selected sheet tray if the image is in anupright position for vertically positioned sheet or if the image is in ahorizontal position with its top end being on the left for horizontallypositioned sheet.

If the orientations are the same at step S22, the ECS 717 sets an angleto 0 degree at step S23, which is then determined as the rotation angleat step S31. If the orientations are not the same at step S22, the ECS717 checks at step S24 whether the orientation of the image is differentfrom the orientation of the sheet. If it is found that the orientationsare different at step S24, the ECS 717 sets an angle to 270 degrees atstep S25, which is then determined as the rotation angle at step S31.

If it is turned out at step S24 that the orientations are not different,the orientations are neither the same nor different. In this case, theECS 717 halts the procedure at step S32 as having failed to identify thecondition. The printing operation is not resumed until proper sheets forprinting are provided.

If step S21 finds that the image is not the first image, the ECS 717checks at step S27 whether the image is oriented in the same directionas the sheet of the first image. If it is oriented in the samedirection, the ECS 717 sets an angle to the rotation angle of the firstimage at step S28, followed by determining this angle as the rotationangle at step S31.

If step S27 finds that the image is not oriented in the same direction,the ECS 717 checks at step S29 whether the image is oriented in adifferent direction than the sheet of the first image. If it is found atstep S29 that the image is oriented in a different direction, the ECS717 sets an angle to the rotation angle of the first image being rotated270 degrees at step S30, followed by determining this angle as therotation angle at step S31. If it is turned out at step S29 that theorientations are not different, the ECS 717 halts the procedure at stepS32 as having failed to identify the condition.

In this manner, scanned images following the first image are aligned inthe same orientation as-the first image, so that all the printed pageswill have images in the same orientation as the first image. That is,printed images are all consistent orientation-wise.

In the following, a description will be given of a procedure usingtab-index sheets and the first image as references, in which imagesfollowing the first image are aligned in the same direction as the firstimage and in the correct positional relation with the tab of thetab-index sheets.

FIG. 7 is a flowchart of the procedure for aligning images in the sameorientation as the first image and in the correct positional relationwith the tab of tab-index sheets.

This procedure is the same as the previous example in that a print-sheettray and an tab-index-sheet tray are selected in the multi-function unit701. In the following, the procedure will be described with reference tothe flowchart.

Upon the start of operation, the multifunction unit 701 scans a stack ofdocument sheets, and selects a print-sheet tray and an tab-index-sheettray. The ECS 717 checks at step S41 whether the orientation of a sheetis the same as the orientation of tab-index sheets. If it is found atstep S41 that the two orientations are the same, the ECS 717 checks atstep S42 whether an image is in the correct positional relationship withthe index tab.

Here, aligning images in the correct positional relationship with theindex tab means arranging images constantly in the same orientation suchas in an upright position or in a horizontal position with the top endof the image being on the left, with such arrangement being kept whenthe tab-index sheets and other print sheets are aligned such that thelonger side of the tab-index sheets matches the longer side of the otherprint sheets.

If it is found at step S42 that the correct positional relationshipexists, the ECS 717 sets a corrective angle to 0 degree at step S43. Ifit is found at step S42 that the image is not in the correct positionalrelationship, the ECS 717 checks at step S44 whether the image beingrotated 180 degrees is in the correct positional relationship with theindex tab.

If it is found at step S44 that the correct positional relationshipexists, the ECS 717 sets a corrective angle to 180 degrees at step S45.If it is found at step S44 that the image is not in the correctpositional relationship, the ECS 717 halts the procedure at step S62 ashaving failed to identify the condition.

If it is found at step S41 that the orientation of the sheet is not thesame as the orientation of the tab-index sheets, the ECS 717 checks atstep S46 whether the image being rotated 270 degrees is in the correctpositional relationship with the index tab. If it is found at step S46that the correct positional relationship exists, the ECS 717 sets acorrective angle to 270 degrees at step S47.

If it turns out at step S46 that the image being rotated 270 degrees isnot in the correct positional relationship, the ECS 717 checks at stepS48 whether the image being further rotated 180 degrees is in thecorrect positional relationship with the index tab.

If it is found at step S48 that the correct positional relationshipexists, the ECS 717 sets a corrective angle to 90 degrees at step S49 byadding 180 degrees to 270 degrees. If it is found at step S48 that thecorrect positional relationship does not exist, the ECS 717 halts theprocedure at step S62 as having failed to identify the condition.

The procedure then moves to step S51 while keeping the corrective anglethat is determined as described above. At step S51, the ECS 717 checkswhether the image is the first image of the document. If it is the firstimage, the ECS 717 checks at step S52 whether the orientation of thesheet is the same as the orientation of this image. If it is found atstep S52 that the orientations are the same, the ECS 717 sets a rotationangle to 0 degree at step S53.

If it is found at step S52 that the orientations are not the same, theECS 717 checks at step S54 whether the orientation of the image isdifferent from the orientation of the sheet. If it is found that theorientations are different at step S54, the ECS 717 sets a rotationangle to 270 degrees at step S55.

If it is turned out at step S54 that the orientations are not different,the ECS 717 halts the procedure at step S62 as having failed to identifythe condition. The printing operation is not resumed until proper sheetsfor printing are provided.

If step S51 finds that the image is not the first image, the ECS 717checks at step S57 whether the image is oriented in the same directionas the sheet of the first image. If it is oriented in the samedirection, the ECS 717 sets a rotation angle equal to the rotation angleof the first image at step S58. If step S57 finds that the image is notoriented in the same direction, the ECS 717 checks at step S59 whetherthe image is oriented in a different direction than the sheet of thefirst image.

If it is found at step S59 that the image is oriented in a differentdirection, the ECS 717 sets a rotation angle equal to the rotation angleof the first image being rotated 270 degrees at step S60. If it isturned out at step S59 that the orientations are not different, the ECS717 halts the procedure at step S62 as having failed to identify thecondition.

The ECS 717 obtains the final rotation angle by adding the correctiveangle previously obtained to the rotation angle obtained above.

According to this procedure, the orientation of images following thefirst image is determined based on the first image and the tab-indexsheets, so that all the printed pages will have images in the sameorientation as the first image and in the correct positionalrelationship with the tab-index sheets. That is, printed images are allconsistent orientation-wise relative to the first image.

A description has been made of the procedure for aligning images in acorrect orientation relative to tab-index sheets by using the index tabas a reference, the procedure for aligning images in the sameorientation as the first image by using the first image as a reference,and the procedure for aligning images in the same orientation as thefirst image and in the correct positional relation with tab-index sheetsby using the first image and the tab-index sheets as references.

In what follows, a description will be given with regard to an actualprinting operation which prints images on tab-index sheets according tothe procedures as described above.

A description will be given first with regard to a message windowdisplayed on the operation unit 30. FIG. 8 is an illustrative drawingshowing the operation unit 30 which displays an index-print-mode key.This index-print mode is used to perform a printing operation that usestab-index sheets, and is used to select a direction in which images arealigned with respect to the tab-index sheets.

In FIG. 8, the same elements as those of FIG. 4 are referred to by thesame numerals, and a description thereof will be omitted.

Among the keys shown in FIG. 8, an index-print-mode key 51 is used toperform a printing operation that uses tab-index sheets. A double-sidekey 325 is used to select double-sided printing. A letter print key 326is used to print a date, a stamp, etc. A combining key 327 is used tocombine two A4 images as one A3 image, for example. A stack key 324 isused to print two copies of each page on a page-by-page basis whenprinting two copies of a single document.

In FIG. 8 as described above, the selection of the index-print-mode key51 by user operation prompts the displaying of a screen for selecting animage orientation of tab-index sheets as illustrated in FIG. 9.

The screen shown in FIG. 9 is used to select the position of the indextab as being either at the top edge, at the bottom edge, at the leftedge, or at the right edge of a sheet. To this end, this screen showsindex position selecting FIGS. 330, 331, 332, and 333 together withcorresponding keys 61, 62, 63, and 64. With these keys, the user canselect the position of an index tab.

Similar settings can be made to each tab-index sheet stored in a tray.Cancel/OK keys 329 are used to cancel or determine the selection of theposition.

In what follows, an example of a printing operation that uses tab-indexsheets will be described.

FIG. 10 is a flowchart of a printing procedure in a case in which thereis a single selected position with respect to printing on tab-indexsheets.

At step S101, the ECS 717 checks whether printing will be performed onsheets inclusive of tab-index sheets. If it is found at step S101 thatprinting will be performed on sheets inclusive of tab-index sheets, theECS 717 computes a rotation angle that is needed to make the tabposition of the image match the tab position of the tab-index sheetsunder the condition that the tab position is at the right-hand side ofthe printed image. When this is done, it is taken for granted that thetab is positioned at the rear end of a sheet being conveyed. Thecomputed rotation angle varies depending on the machine construction asto the direction of sheet conveyance, as to whether an image formationsurface is an upper surface or a lower surface, etc.

The machine construction is part of the specifications of themulti-function unit 701. Such specifications may define the position ofthe tab as being at the rear end, may define the direction in whichsheets are conveyed, and may define which one of the upper side and thelower side of a sheet will have an image formed thereon.

At step S103, the ECS 717 checks whether there is an instructionregarding the position of a tab relative to the image. If there is aninstruction, at step S104, the ECS 717 corrects the rotation angle ofthe image according to the selected position of the tab relative to theimage. If it is found at step S103 that there is no instruction, theprocedure moves to step S105.

At step S105, the ECS 717 checks whether the tab of the index sheet issituated at the rear end. If it is found at step S105 that the tab isnot at the rear end, at step S106, the ECS 717 corrects the rotationangle of the image according to the tab position of the tab-index sheet.With this, the procedure comes to an end.

In this manner, when the tab of a tab-index sheet is located at the rearend of the sheet being conveyed, the rotation angle of an image isdetermined relative to the reference rotation angle at which the imageis positioned to have the tab at the right-hand side thereof. Suchdetermination is made based on the orientation of the image and thespecified direction of the index tab relative to the image. If the indextab should come at the top edge, the image needs to be rotated 90degrees clockwise. If the index tab should come at the left-hand-sideedge, the image needs to be rotated 180 degrees clockwise. If the indextab should come at the bottom edge, the image needs to be rotated 270degrees clockwise. Here, the orientation of an image refers to theorientation of a scanned image in the case of copying, or refers to theorientation of an image supplied from an external device.

If the index tab is located on the left-hand side relative to thedirection in which a sheet is conveyed, a further 90-degree clockwiserotation is necessary. If the index tab is located at the front end inthe direction in which a sheet is conveyed, a further 180-degreeclockwise rotation is necessary. If the index tab is located on theright-hand side relative to the direction in which a sheet is conveyed,a further 270-degree clockwise rotation is necessary.

FIG. 11 is an illustrative drawing showing the way an image is printedas described above.

FIG. 11 shows a type 401 having a tab on the longer side, and furthershows a type 402 having a tab on the shorter side. Depending on the typeof a tab-index sheet, the rotation angle of an image being printed iscontrolled, so that printing is properly done for 4 different tabdirections as shown in FIG. 11.

FIG. 12 is an illustrative drawing showing the way an image is printedwhen the image having a size as shown by dotted lines can fit in thetab-index sheet regardless of the orientation of the image.

In the following, a description will be given of a case in whichdocument images to be printed on tab-index sheets are a mixture ofportrait images and landscape images.

When different types of tab-index sheets are provided for use forprinting, specifying only one direction as the direction of an index tabrelative to an image may result in the image failing to fit in eithertype of the tab-index sheets. That is, part of the image may slip beyondthe edge of the sheet, thus failing to be printed. If two directions arespecified as the direction of an index tab, the image being printed canfit in a given type of a tab-index sheet by choosing one of thespecified directions so as to maintain a match between the direction ofthe tab of the tab-index sheet and the specified tab direction of theimage.

FIG. 13 is a flowchart of a procedure for printing images by specifyingtwo preferred directions as the direction of an index tab.

At step S201, the ECS 717 checks whether printing involves tab-indexsheets. If the tab-index sheets are not involved, the ECS 717 completesthe procedure.

At step S202, the ECS 717 checks whether there is any particular settingfor the direction of an index tab relative to an image. If there is noparticular setting, the ECS 717 completes the procedure.

If there is a setting for the direction of an index tab relative to animage, the ECS 717 selects one of the two specified directions (whichare adjacent to each other) such that the orientation of the sheetmatches the orientation of the image.

At step S204, the ECS 717 corrects the rotation angle of the image inconformity with the direction of the tab of the tab-index sheets. Withthis, the procedure comes to an end.

FIG. 14 is an illustrative drawing showing images that are printedaccording to the procedure of FIG. 13. In FIG. 14, images to be printedon tab-index sheets include two types of images, i.e., portrait imagesand landscape images that are equal in size.

Document images 1 and 2 are portrait, and document images 3 and 4 arelandscape. A print example 601 corresponds to a case in which only oneposition of the index tab is specified. A print example 602 correspondsto a case in which two positions of the index tab are specified.

In the print example 601, only one position, i.e., the right-hand sideof an image, is specified as the direction of an index tab. Because ofthis, an index tab is invariably provided on the right-hand side whetherthe image is a portrait or a landscape. In this case, two types oftab-index sheets need to be provided to ensure proper printing.

In the print example 602, on the other hand, two directions that areadjacent to each other are specified as the position of an index tab,i.e., the right-hand side and the topside or the right-hand side and thebottom side. In this case, images are rotated as necessary, so that onlyone type of tab-index sheets is needed to print both a portrait imageand a landscape image.

In what follows, a description will be given of a case in whichtab-index sheets stacked in tray have the same size as images, and havethe same direction or a different direction. In this case, tab-indexsheets having the same direction and the same size as images are givenhigher priority.

If no proper sheets are provided in a tray, or proper sheets having twodifferent sizes are provided in trays, the size of a higher-prioritysheet is regarded as the size of a tab-index sheet to be printed. Ifthere is a sheet of a relevant size, printing is performed. If sheetshaving proper size are not provided, a request is made for the settingof sheets that are equal in size to the higher-priority sheet.

With reference to FIG. 15, at step S301, the ECS 717 checks whetherprinting involves tab-index sheets. If the printing does not involvetab-index sheets, the ECS 717 brings the procedure to an end.

If the printing involves tab-index sheets, the ECS 717 checks at stepS302 whether the tab-index sheets having proper size are provided fortwo specified directions.

If the tab-index sheets having proper size are provided for the twospecified directions, the ECS 717 proceeds to step S303. Otherwise, theECS 717 moves to step S304.

At step S304, the ECS 717 checks whether tab-index sheets having theproper size are provided. If tab-index sheets having the proper size areprovided, the ECS 717 brings the procedure to an end. If tab-indexsheets having the proper size are not provided, the ECS 717 proceeds tostep S303.

At step S303, the ECS 717 selects the size of a sheet having a preferreddirection (higher-priority direction) as a proper size. At step S305,the ECS 717 checks whether tab-index sheets having the proper size areprovided. If tab-index sheets having the proper size are not provided,the ECS 717 moves to S306, and requests the setting of sheets that areequal in size to the sheet having the preferred direction. If it isfound at step S305 that tab-index sheets having the proper size areprovided, the ECS 717 brings the procedure to an end. Here, requestingthe setting of sheets means requesting the displaying of a message onthe operation unit 30 that prompts a user to set the sheets.

In what follows, FIG. 16 will be referred to, and a description will begiven of a case in which a mode involving tab-index sheets and apunching mode are both used. In the following, stapling may be exchangedfor punching.

If the printing mode indicates printing that involves tab-index-sheets,the rotation angle of an image is computed from the specified indexposition, the orientation of an image, and the machine structure toprovide the consistency of orientations where the index tab is situatedat the rear end of a sheet being conveyed. If a punching mode is alsospecified, printing is suspended if the position of punched holes andthe direction of index-tabs do not match.

The procedure shown in FIG. 16 is comprised of a series of branchinstructions, each of which will be described. Step S501 checks whetherprinting involves tab-index sheets.

Step S502 checks whether the position of an index tab relative to animage is specified.

Step S503 checks whether punching is requested.

Step S504 checks whether the specified position of punch holes do notmatch the specified position of an index tab.

If all the conditions checked at steps S501 through S504 are satisfied,the ECS 717 suspends the procedure at step S505. If any one of theseconditions is not satisfied, the ECS 717 brings the procedure to an end.

FIG. 17 is an illustrative drawing showing variations of the combinationof the specified position of an index-tab and the specified position ofpunch holes. Here, a punching mechanism is assumed to be only capable ofpunching at the front end of a sheet being conveyed. If the position ofa tab is specified to be on the right-hand side with respect to aportrait image, the punch holes can be made as shown in a punch example334. In the case of a landscape image, however, punching as shown in apunch example 335 is not possible if the position of a tab is specifiedas being on the right-hand side.

With the position of a tab being on the right-hand side, therefore,printing should be suspended if the position of punch holes is specifiedas being on the top side or the bottom side.

When the direction of a tab is specified as being on the bottom side asshown in the punch example 335, punch holes can be made only on the topside. If the position of punch holes is specified as being on the rightor on the left, printing should be suspended.

FIG. 18 is a flowchart of a procedure for warning a user upon suspensionof a job.

Steps S601 through S605 of this flowchart are identical to steps S501through S505 of FIG. 16, and a description thereof will be omitted. Ifthe ECS 717 suspends a job (procedure) at step S605, then, the ECS 717displays a warning message at step S606. With this, the procedure comesto an end.

In response to the warning message, a user can give an instruction tomatch the position of punch holes with the direction of an index tab,followed by giving an instruction to resume the operation.

In the present invention, the CPU of a computer serving as an imageforming apparatus executes programs to perform the procedures asdescribed above where the programs are written in any programminglanguage that provides instructions to be fed to the CPU. Such programsmay be stored in a computer-readable record medium such as a CD-ROM, aDVD-ROM, a flexible disk, an MO, etc.

These programs may be loaded to the image forming apparatus from therecord medium, or may be downloaded to the image forming apparatus viaelectro-communication lines such as a network, thereby enabling theimage forming apparatus to print document images in tab-index sheets asdescribed above.

Further, the present invention is not limited to these embodiments, butvarious variations and modifications may be made without departing fromthe scope of the present invention.

The present application is based on Japanese priority applications No.2002-067572 filed on Mar. 12, 2002, No. 2002-067573 filed on Mar. 12,2002, and No. 2003-38748 filed on Feb. 17, 2003, with the JapanesePatent Office, the entire contents of which are hereby incorporated byreference.

1. An image forming apparatus which prints images on print sheets andinserts tab-index sheets between the printed print sheets, the imageforming apparatus comprising: an orientation detecting unit whichdetects an orientation of a print sheet being supplied based on a trayfrom which the print sheet is supplied; a rotation-angle selecting unitwhich selects, automatically, without user intervention, a rotationangle of an image in order to match the orientation of the image to thedetected orientation of the print sheet and a predetermined positionalrelationship with a tab of the tab-index sheets, the predeterminedpositional relationship indicating a position of the tab as being eitherat a top edge, at a bottom edge, at a left edge, or at a right edge of atab-index sheet with respect to the image in an upright position; and aprinting unit which prints the image being rotated by the selectedrotation angle such that the tab comes at the position indicated by thepredetermined positional relationship relative to the printed image,wherein said rotation-angle selecting unit checks whether the image is afirst image, said rotation-angle selecting unit arranging the image inan orientation matching an orientation of the print sheet upon findingthat the image is the first image, and said rotation-angle selectingunit arranging the image in an orientation matching an orientation of asheet on which the first image is printed upon finding that the image isnot the first image.
 2. A non-transitory computer-readable medium havinga program embodied therein for causing a processor to select a rotationangle of an image that is to be printed by an image forming apparatususing tab-index sheets, said program comprising: a program codeconfigured to detect an orientation of a print sheet being suppliedbased on a tray from which the print sheet is supplied; a program codeconfigured to automatically, without user intervention, select therotation angle of the image based on arranging the image in anorientation matching the detected orientation of the print sheet and apredetermined positional relationship with a tab of the tab-indexsheets, the predetermined positional relationship indicating a positionof the tab as being either at a top edge, at a bottom edge, at a leftedge, or at a right edge of a tab-index sheet with respect to the imagein an upright position; a program code configured to check whether theimage is a first image; and a program code configured to select therotation angle of the image based on arranging the image in anorientation matching an orientation of the print sheet upon finding thatthe image is the first image, and selecting the rotation angle of theimage based on arranging the image in an orientation matching anorientation of a sheet on which an image previously identified as thefirst image is printed upon finding that the image is not the firstimage.
 3. A non-transitory computer-readable medium having a programembodied therein for causing a processor to select a rotation angle ofan image that is to be printed by an image forming apparatus usingtab-index sheets and to control printing of the image that is printed bythe image forming apparatus using tab-index sheets, said programcomprising: a program code configured to detect an orientation of aprint sheet being supplied based on a tray from which the print sheet issupplied; a program code configured to allow selection of a position ofa tab relative to the image, which is not printed on the tab, theselected position of the tab indicating a position of the tab as beingeither at a top edge, at a bottom edge, at a left edge, or at a rightedge of a tab-index sheet with respect to the image in an uprightposition; a program code configured to automatically, without userintervention, select the rotation angle of the image based on arrangingthe image in an orientation matching the detected orientation of theprint sheet and a predetermined positional relationship with a tab ofthe tab-index sheets, the predetermined positional relationshipindicating the selected position of the tab as being either at a topedge, at a bottom edge, at a left edge, or at a right edge of atab-index sheet with respect to the image in an upright position; and aprogram code configured to rotate the image based on the selectedrotation angle of the image to position a tab of the tab-index sheet atthe selected position of the tab relative to the image.
 4. Anon-transitory computer-readable medium having a program embodiedtherein for causing a processor to select a rotation angle of an imagethat is to be printed by an image forming apparatus using tab-indexsheets and to control printing of the image that is printed by the imageforming apparatus using tab-index sheets, said program comprising: aprogram code configured to detect an orientation of a print sheet beingsupplied based on a tray from which the print sheet is supplied; aprogram code configured to allow selection of two positions of a tabrelative to the image, which is not printed on the tab, each of the twoselected positions of the tab indicating a position of the tab as beingeither at a top edge, at a bottom edge, at a left edge, or at a rightedge of a tab-index sheet with respect to the image in an uprightposition; a program code configured to automatically, without userintervention, select the rotation angle of the image based on arrangingthe image in an orientation matching the detected orientation of theprint sheet and a predetermined positional relationship with a tab ofthe tab-index sheets, the predetermined positional relationshipindicating the selected position of the tab as being either at a topedge, at a bottom edge, at a left edge, or at a right edge of atab-index sheet with respect to the image in an upright position; and aprogram code configured to rotate the image based on the selectedrotation angle of the image to position a tab of the tab-index sheet ateither one of the two selected positions relative to the image.
 5. Anon-transitory computer-readable medium having a program embodiedtherein for causing a processor to select a rotation angle of an imagethat is to be printed by an image forming apparatus using tab-indexsheets and to control printing of the image that is printed by the imageforming apparatus using tab-index sheets, said program comprising: aprogram code configured to detect an orientation of a print sheet beingsupplied based on a tray from which the print sheet is supplied; aprogram code configured to allow selection of two positions of a tabrelative to the image, which is not printed on the tab, while specifyingone of the two positions as a preferred position, each of the twoselected positions of the tab indicating a position of the tab as beingeither at a top edge, at a bottom edge, at a left edge, or at a rightedge of a tab-index sheet with respect to the image in an uprightposition; a program code configured to automatically, without userintervention, select the rotation angle of the image based on arrangingthe image in an orientation matching the detected orientation of theprint sheet and a predetermined positional relationship with a tab ofthe tab-index sheets, the predetermined positional relationshipindicating the selected position of the tab as being either at a topedge, at a bottom edge, at a left edge, or at a right edge of atab-index sheet with respect to the image in an upright position; and aprogram code configured to rotate the image based on the selectedrotation angle of the image to position a tab of the tab-index sheet ateither one of the two selected positions of a tab relative to the image,where said specified one of the two selected positions is preferred overanother one if both of the two selected positions of the tab relative tothe image match the position of a tab of the tab-index.
 6. Thecomputer-readable medium as claimed in claim 3, wherein said programfurther comprises a program code unit configured to suspend the printingof the image and notify a user if the selected position of the relativeto the image does not match the position of a tab of the tab-indexsheets.
 7. The computer-readable medium as claimed in claim 4, whereinsaid program further comprises a program code unit configured to suspendthe printing of the image and notify a user if the position of the tabof the tab-index sheets does not match either one of the two selectedpositions of a tab relative to the image.
 8. The computer-readablemedium as claimed in claim 5, wherein said program further comprises aprogram code unit configured to suspend the printing of the image andnotify a user if the position of the tab of the tab-index sheets doesnot match either one of the two selected positions of a tab relative tothe image.
 9. The computer-readable medium having a program as claimedin claim 2, wherein the image is not printed on the tab.